1. Field of the Invention
This invention relates generally to projectiles having improved glide pins. More particularly, the present invention pertains to a puck having a plurality of apertures, each containing a bipartite pin, wherein each mating component of the pin includes a shank having an angularly inclined toothed surface, which when joined within a puck aperture forms a glide pin.
2. Description of the Prior Art
In-line skates have inspired renewed interest in playing street hockey. Similar to ice hockey, the players drive a puck into an opposing team's goal to score points. Unlike in ice hockey, the puck typically does not slide as easily along a street hockey playing surface, typically cement or asphalt, as it would on ice. Players of street or roller hockey often must retrace their paths to reclaim the projectile, slowing the game and making it less enjoyable. The puck oftentimes flips upon its edge and rolls across the playing surface rather than playing flat, or sliding along on one of its two faces. Another problem with using a conventional street hockey puck to play roller hockey is that it tends to rebound off objects with high energy at unpredictable trajectories. As roller hockey technology improves, players become less tolerant of inadequate playing characteristics exhibited by conventional hockey pucks. A need exists for a puck that glides easily on a street or court hockey playing surface, tends to play flat, provides low-energy rebound action, provides long pin-life and discourages rolling on its edge.
These advantageous properties of a puck used to play street hockey are largely dependent on the glide pins used during the manufacturing process. Due to the high shear forces exerted upon the puck during play, inadequately designed pins often cause pin heads to be sheared off and fall out, thus destroying the life and usefulness of the puck. Surface wear further causes the pin heads to wear down and cause the pin to fall out of the puck. However, manufacturing concerns, such as cost and speed of manufacturing each puck, act against the use of quality pins.
In many manufacturing processes, a molding process is used to inject hot, fluid plastic into a mold which provides a plurality of predetermined diameter apertures into the puck, each aperture being sized to exact tolerances to receive a pin shank. The head of the pin, whether recessed into the surface of the puck or not, resides above the general plane of the puck body, thereby elevating the puck to permit it to glide over surfaces with high coefficients of friction, such as a concrete surface. However, several factors cause problems to the successful insertion of such pins into the puck, which in turn effect the useful life and shear force resistance of the pins within the puck.
First, as the plastic of the puck body cools after injection, the plastic shrinks, thus causing the aperture formed to receive the pin to increase. This provides an potential advantage to a pin which can alter its diameter. For purposes of being inserted into a puck, a reduced diameter pin is desired. However, after final assembly, a pin having a snug fit within the aperture, and thus a diameter as close to that of the aperture, to grip the puck, is also advantageous.
These conflicting advantages present manufacturing problems. If the pin can be inserted early enough in the process, the shrinkage of the plastic body results in a loss of gripping force upon the pin and increases the chance of the pin being lost over the life of the puck. However, during the shrinking process, the plastic is subject to damage by an improperly inserted pin, such as jabbing by a sharp object such as the pin's tip. Thus, unless a pin can be inserted without contact through the mouth of the aperture, the risk of a damaged puck is high, and consequently the process is slowed down until a threshold temperature is reached where a pin can be inserted without fear of damage.
Even then, a pin which must be inserted into a predetermined diameter aperture cannot have a shank diameter of greater than or closely approaching the aperture diameter and provide an expectation of an improved grip within the aperture against the wall of the puck body. None of the pucks in the prior art, nor bipartite or split pins known in the art, are properly configured to serve the needs of the puck manufacturer. Thus, a need for an improved glide pin is seen.
Several types of game pucks are described in the patent literature. Unfortunately, the devices described in the prior art do not predispose a puck to the above described requirements.
Most notably, U.S. Pat. No. 5,275,410, issued Jan. 4, 1994, to Bellehumeur et al., and U.S. Pat. No. 5,482,274, issued Jan. 9, 1996 to Bellehumeur, describe a puck for use on a non-ice surface. The puck includes a solid core having an upper face, a lower face and an annular surface with a plurality of annular slots and throughbores radially diverged therethrough. The slots provide spring means that deform on impact. Stainless steel or polyurethane runners, i.e. glide pins, are received in each throughbore, each having a head protruding above each face. One embodiment of a runner shows it formed in two pieces. In particular, as shown in FIG. 17 of the '410 patent, one piece has an axial bore with interior annular teeth that engage with the exterior annular teeth of the second piece inserted therein. However, such pin has a fixed diameter determined by one component part, and has an axial arrangement that prevents it from being used as described above. In essence, the throughbore will reach a predetermined diameter after cooling and only then can the runner be safely inserted into the throughbore without damaging the sidewalls of the throughbore. Moreover, the pin must be inserted in nearly perfect coaxial and concentric alignment with the throughbore, and will still not derive the benefit of an tight fit.
Other less relevant pucks include, for example, U.S. Pat. No. 3,675,928, issued Jul. 11, 1972, to Salvatore A. Gentile, describes an impact safety game puck. The apparatus includes a solid core with a peripherally-disposed annular chamber. A second embodiment includes a thin disk having two faces and a wide, peripherally-disposed annular chamber, defining bowl-shaped cavities in each face of the disk.
U.S. Pat. No. 3,726,526, issued Apr. 10, 1973, to Leroy N. Radovich, describes a multi-purpose game puck. The device includes a solid core having an upper face, a lower face and an annular surface. The device has a central recess and a plurality of indented surfaces radially diverged in each face.
U.S. Pat. No. 3,784,204, issued Jan. 8, 1974, to Julius Felber, describes a hockey puck. The apparatus includes a solid core having an upper face, a lower face and an annular surface. The apparatus has central recesses in each face. The apparatus includes a plurality of spherical rollers radially diverged and slidingly maintained on each face.
U.S. Pat. No. 4,793,769, issued Dec. 27, 1988, to Michael Dolan, describes a hockey puck having a solid core with an upper face, a lower face and an annular surface. The device includes a plurality of ball bearings, radially diverged and slidingly received in the core. The ball bearings protrude through each face.
U.S. Pat. No. 5,207,720, issued May 4, 1993, to Charles G. Shepherd, describes a hockey puck device having a first housing and a second housing which threadingly interengage to define a cavity. Gage means are disposed within the cavity for measuring impact forces.
U.S. Pat. No. 5,366,219, issued Nov. 22, 1994, to William Salcer et al., describes a hockey puck which includes an insert member over which plastic material is molded. The finished device has an upper face, a lower face and an annular surface. The insert has runners that protrude through and are radially diverged about the periphery of each face. The runners are constructed from nylon, possibly blended with "Kevlar.TM.."
Other pucks failing to show the pin of the present invention include U.S. Pat. No. 4,111,419 issued to Pellegrino, U.S. Pat. No. 5,207,720 issued to Shepherd, and U.S. Pat. No. 4,078,801 issued to White, Sr.
Of the bipartite pins known in the prior art, U.S. Pat. No. 5,074,696 issued to Tanaka is notable in its disclosure of securing pairs of fasteners, each with engagement teeth. However, this fastener assembly would not be suitable in the present application for a plastic molded puck. First, the teeth of the Tanaka fastener are aligned substantially along a single plane substantially perpendicular to a central axis passing concentrically through the head of the pin, as well as nearly parallel to the peripheral wall of the shank. Thus, the tip of the pin is almost one half of the total diameter of the shank when joined together. Such a configuration teaches away from the structure of the present invention. Moreover, Tanaka fails to describe or teach the use of a reduced tip size as an important factor in the insertion of quality runners or glide pins during the manufacturing process of a puck to increase the useful life of the puck.
Other patents describing pins for binding loose leaves which suffer from the above described and other disadvantages include U.S. Pat. No. 2,201,551 issued to Welk and U.S. Pat. No. 1,418,314 issued to McBee. An toothed insulator is shown in U.S. Pat. No. 607,315 issued to Wingard, and an inclined split bolt is shown in U.S. Pat. No. 150,060 issued to Lapham.
The above shortcomings of the prior art demonstrate a need for a game puck having an improved glide pin. None of the above references, taken alone or in combination, are seen as teaching or suggesting the presently claimed game puck.